This invention relates to a rail assembly for underground coal-getting or mining machines, such as wheeled coal-cutting machines, the assembly being mounted on a coal conveyor comprising a plurality of conveyor pans to connected end-to-end, and the assembly comprising a rail section mounted on each pan. Each rail section includes rail elements interconnected for relative longitudinal movement so that the upper surfaces of the rail sections will be made to lie parallel to the central axes of the conveyor pans even when those axes are angularly related.
A known assembly of this general type has each of its rail sections made up of rail elements equal to twice the number of conveyor pans. An element of each section is fixedly mounted on a conveyor pan at the central portion of the pan, and the other rail element spans each joint between adjoining rail sections and is interconnected with the fixed rail elements for longitudinal movement relative thereto and relative to the conveyor. Relative longitudinal movement between the rail elements must be limited to assure a relatively smooth movement of the coal cutter wheels therealong. Thus, the clearance between a pair of adjoining conveyor pans, when the central axes thereof are angularly related to accomodate an undulating conveying path, may be only twice as large as the clearance between the fixed and relatively movable rail elements of the rail sections. However, because of the small clearances between the rail elements which must be maintained, even twice as large clearances between adjoining conveyor pans is too limiting for most applications.